(i) Technical Field
The present invention relates to a developing device and an image forming apparatus using such developing apparatus.
(ii) Related Art
Some of image forming apparatus represented by a printer, a copying machine and a similar machine using an electrophotographic system or an electrostatic recording system employ, as a developing device for developing a latent image to be formed on an image hold member such as a light sensitive member, a developing device which uses a developer (such as a two-component developer) containing toner and magnetic carriers.
In such developing device, generally, a developer stored in a portion of a housing (a case) is held by a magnetic force on a developing roller which is disposed with a portion thereof exposed to an opening facing a developing area opposed to the image hold member of the housing and also which can be rotated, and, after then, the thus-held developer is delivered to a developing area in such a manner that the layer thickness of the developer is regulated to a given thickness by a layer thickness restrict member. And, the developer (toner component) on the developing roller delivered to the developing area is electrostatically adhered to the latent image portion of the image hold member, thereby developing the electrostatic latent image. In this case, as the developing roller, there is mainly used a developing roller which is composed of a rotatable cylindrical-shaped sleeve and a magnet roller which is disposed such that it is positioned and fixed within the internal space of the sleeve and also in which there are provided two or more magnetic poles.
In the above-mentioned developing device, there is a possibility that the developer can fly around and float up to the outside from the area of the housing opening on the side where the outer peripheral surface of the developing roller passes after it passes through the developing area. Also, when the flying phenomenon of the developer occurs, there is a fear that the interior of the image forming apparatus can be contaminated by the developer, or, after such developer accumulates on the developing device and the like, the developer can be dropped down due to vibrations or the like to thereby result in a poor image.